diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index def54ae6a67e9998096734c17aa4c122fcf48de8..f6464c7aa8d3c33d6e069ed433f3fc0c310e4070 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,14 +2,10 @@ stages:
   - build
 
 build:
-  image: debian:stable
+  image: debian:oldstable
   stage: build
   script:
-  - apt-get install software-properties-common
-  - add-apt-repository ppa:openjdk-r/ppa
-  - apt-get update
-  - apt install openjdk-11-jre-headless
-  - apt-get -y install graphviz wget
+  - apt-get update && apt-get -y install graphviz openjdk-11-jre-headless wget
   - wget http://sourceforge.net/projects/plantuml/files/plantuml.1.2022.6.jar/download --output-document=plantuml.jar --quiet
   - java -jar plantuml.jar -charset UTF-8 -o diagrams modellierung/*
   - mkdir public/